CN102559302A - Diesel pour point depressant and preparation method thereof - Google Patents

Abstract

The invention belongs to the technical field of diesel oil additives, in particular to a diesel pour point depressant and a preparation method thereof. The diesel oil pour point depressant overcomes the defects existing in the existing pour point depressants, can greatly reduce the cold filter point and freezing point of diesel oil, is widely applicable to various diesel oils, and has little limitation.

Description

A kind of diesel oil pour point depressant and preparation method thereof

technical field

The invention belongs to the technical field of diesel oil additives, in particular to a diesel pour point depressant and a preparation method thereof.

Background technique

Ordinary diesel oil contains more straight-chain alkanes, so it is easy to condense into paraffin and precipitate when the temperature is low, which will block the oil circuit of the diesel engine and affect the normal operation of the engine. Therefore, diesel vehicles in northern my country use low-grade diesel when the temperature is low. Correspondingly, oil refineries in northern my country begin to produce low-grade diesel oil in winter, and this process is realized by adding pour point depressants to ordinary diesel oil. Diesel pour point depressant, also known as diesel low-temperature fluidity improver, is widely used in petroleum refining, transportation, storage, and use. It is of great significance for increasing the ratio of diesel to gasoline, increasing diesel, and improving the economic benefits of refineries.

The copolymer of ethylene and unsaturated ester is a kind of diesel oil pour point depressant that is widely used at present, such as the polyethylene-ethyl acetate disclosed in U.S. Patent No. 3,048,479. Filter point effect is not obvious. As mentioned in U.S. Patent U.S.P3961916, two kinds of ethylene-vinyl acetate copolymers with different vinyl acetate concentrations and relative molecular weights are used, one is used as a wax crystal inhibitor, and the other is used as a nucleating agent, synergistically It can greatly reduce the cold filter point of middle distillate fuel oil, but the pour point depressant has poor sensitivity to diesel oil with high wax content, and the pour point depressant effect is not obvious; at the same time, the polar group content of the pour point depressant is too high High (greater than 33%) or too low (less than 18%) are not conducive to pour point depressing. Only when it is in the middle range (about 28%) can the pour point depressant achieve a good depressing effect, which is difficult to control. In addition, U.S. Patent U.S.P4022590 introduced that α-olefin homopolymerization or copolymer is also used as a pour point depressant. The use effect of the pour point depressant is related to the composition of the ester in the polymer and the average carbon number of the ester side chain. The singleness is high, and its selectivity must be paid attention to in research and application, so the universality of this kind of pour point depressant is not high, and the reduction of the cold filter point of diesel oil is not large.

The pour point depressing effect of single use of a certain polymer is limited, and the universality of application to diesel is also limited. The current commonly used method is to compound several polymers. U.S. Patent U.S.P6017370 has reported that ethylene-vinyl acetate-fumarate copolymer is compounded with hydrocarbyl substituted succinic acid and diethanolamine amides, which can effectively reduce the Cloud point of fuel oil and improved low temperature properties.

The above-mentioned pour point depressants have certain limitations. Due to the single type of polymer in the components of some pour point depressants, or because the compounding of several polymers is not ideal, the scope of application of the existing pour point depressants is limited. It has little effect on some diesel oils, or the degree of lowering the freezing point and cold filter point is too small.

Contents of the invention

The purpose of the present invention is to address the above problems, to provide a new diesel oil pour point depressant, to overcome the defects existing in the existing pour point depressant, can greatly reduce the cold filter point and freezing point of diesel oil, and is widely applicable to various diesel oil , with small limitations.

Technical scheme of the present invention is: diesel oil pour point depressant of the present invention is made up of following components by weight:

10-20 parts of ethylene-vinyl acetate copolymer, 20-30 parts of styrene-stearyl maleate copolymer, 20-30 parts of polymethacrylate, 5-10 parts of nonionic surfactant, 200 parts No. 25-35 parts of solvent naphtha.

The ethylene-vinyl acetate can be purchased commercially, or can be prepared according to the following method: put vinyl acetate and ethylene into the autoclave at a molar ratio of 1:2~2.4, and control the pressure at 10~15Mpa , The temperature is 170~190 ℃, with 1wt% initiator azobisisobutyronitrile or benzoyl peroxide, and the polymerization reaction is 3~4 hours, and the ethylene-vinyl acetate copolymer can be prepared.

Described styrene-stearyl maleate copolymer can be purchased commercially, also can make according to following method: styrene and maleic anhydride are added reactor according to molar ratio 1:2～2.2, with Use dibenzamide peroxide as an initiator, use toluene as a solvent, heat up to 110-130°C under constant stirring, and react for 4-6 hours to obtain a styrene-maleic anhydride copolymer. Equimolar stearyl alcohol is esterified with p-toluenesulfonic acid as a catalyst at 150°C to 170°C to obtain styrene-stearyl maleate copolymer.

The polymethacrylate is prepared by the following method: methacrylic acid and pentanol, hexanol, heptanol, octanol, lauryl alcohol and stearyl alcohol are prepared according to the acid-alcohol molar ratio of 1:1.5~2 Ratio into the reaction kettle, the molar ratio of each alcohol is arbitrary, and esterified at 150~170°C for 3 hours to obtain monomeric ester. Then, 0.5 wt% tetra-n-butyl titanate was added to these monomer esters as a polymerization catalyst and polymerized at 200°C for 6 hours to obtain polymethacrylate.

The nonionic surfactants are: 1-2 parts by weight of hydroxyethyl cellulose and 3-8 parts by weight of hydroxypropyl methylcellulose.

The method for preparing diesel oil pour point depressant of the present invention is, comprises the following steps:

(1) Add 5-10 parts of nonionic surfactant to 25-35 parts of No. 200 solvent oil, and disperse at 50°C for 20-30 minutes;

(2) Take 10-20 parts of ethylene-vinyl acetate copolymer, add it to the above system, and disperse for 10 minutes at room temperature;

(3) Take 20-30 parts of styrene-stearyl maleate copolymer, add it to the above system, and disperse at room temperature for 10 minutes;

(4) Take 20-30 parts of polymethacrylate, add it to the above system, and disperse for 10 minutes at room temperature;

(5) After uniform dispersion, the diesel pour point depressant is obtained.

The beneficial effect of diesel oil pour point depressant of the present invention is:

(1) The pour point depressant of the present invention has universal applicability to diesel.

The diesel pour point depressant of the present invention is reasonably matched according to the molecular structure of each component, and can have a significant pour point depressant effect on the standard diesel produced by most domestic refineries. After the pour point depressant of the present invention is added to diesel oil at low temperature, its components play a synergistic and complementary role, so that the additive not only co-crystallizes with the n-alkane in diesel oil to form the crystal nucleus of paraffin crystals, but also makes the formed crystal particles as much as possible Disperse evenly, so that the diesel oil maintains good low temperature fluidity. Provide the effect data of the product of the present invention as shown in Table 1.

Table 1 Comparison of the use effect of the product of the present invention and other pour point depressants

Among them, PAE: advanced polymethacrylate, T1804: polyethylene-vinyl acetate pour point depressant, EVA: ethylene-vinyl acetate copolymer.

The analysis shows that: T1804 and EVA can reduce the cold filter point of Xianyang 0# diesel and Dagang 0# diesel by 1-2°C, PAE by 4°C, and the product of the present invention can reduce the cold filter point by 4-5°C, showing certain advantages. For 0# diesel oil in North China and 0# diesel oil from Fushun No. 5 Plant, T1804 and EVA could not reduce the cold filter point, and even increased by 1-3°C, PAE decreased by 2-4°C, but the product of the present invention can reduce the cold filter point by 3- 6°C, significantly better than T1804 and EVA. In summary, it can be seen from the above results that although the pour point depressant effect of the pour point depressant described in the present invention is not much different from the optimal value of other pour point depressants in a certain type of diesel oil, the present pour point depressant has no significant effect on various types of diesel oil. All have good pour point depressing effects and are universal.

(3) The pour point depressant of the present invention has good dispersibility, can quickly dissolve with diesel oil, and prevents paraffin crystals in diesel from forming a three-dimensional network structure.

The interaction between paraffin crystals in diesel oil forms a three-dimensional network structure, which wraps the uncondensed oil and makes the oil lose its fluidity. The pour point depressant of the invention has good dispersibility, can quickly dissolve with diesel oil, makes the paraffin crystal particles in the diesel oil suspend in the diesel oil, and cannot collide with each other in a three-dimensional network structure, thereby improving the low-temperature fluidity of the diesel oil. Provide the effect data of the product of the present invention as shown in Table 2.

Table 2 Comparison of the effect of the present invention and other commercially available products on low temperature fluidity of diesel oil (mPa·S)

Among them, LAS: sodium dodecylbenzenesulfonate, SBS: sodium dodecylsulfonate, NP-10 fatty alcohol polyoxyethylene ether, OP-15: octylphenol polyoxyethylene ether.

It can be seen from the analysis that the product of the present invention has a good low-temperature fluidity and viscosity-reducing effect.

Detailed ways

The technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

Example 1

1. Preparation of ethylene-vinyl acetate

Put vinyl acetate and ethylene into the autoclave according to the molar ratio of 1:2, control the pressure at 10Mpa, temperature 180°C, use 1wt% initiator azobisisobutyronitrile, and polymerize for 3 hours to obtain ethylene- Vinyl acetate copolymer.

2. Preparation of Styrene-Stearyl Maleate Copolymer

(1) Add styrene and maleic anhydride to the reactor at a molar ratio of 1:2, use dibenzamide peroxide as the initiator, and use toluene as the solvent, heat up to 110°C under constant stirring, and react for 4 hours. That is, a styrene-maleic anhydride copolymer was obtained.

(2) Add stearyl alcohol which is equimolar to maleic anhydride, use p-toluenesulfonic acid as a catalyst, and perform esterification at 150°C to obtain a styrene-stearyl maleate copolymer.

3. Preparation of polymethacrylate

(1) Add methacrylic acid, amyl alcohol, hexanol, heptanol, octanol, lauryl alcohol, and stearyl alcohol to the reaction kettle according to the molar ratio of 1:1.5, and the molar ratio of each alcohol is any ratio , Esterified at 150°C for 3 hours to obtain a monomeric ester.

(2) Add 0.5wt% tetra-n-butyl titanate to the monomer ester as a polymerization catalyst and polymerize at 200°C for 6 hours to obtain polymethacrylate.

4. Prepare pour point depressants A to F in different parts by weight

A. In parts by weight, 15 parts, 30 parts, 30 parts, 5 parts, 20 parts of ethylene-vinyl acetate copolymer, styrene-stearyl maleate copolymer, polymethacrylic acid Esters, nonionic surfactants, No. 200 solvent oil, using tetra-n-butyl titanate as a polymerization catalyst, and polymerizing for 6 hours at a temperature of 200°C, to obtain diesel oil pour point depressant product A, (the nonionic The surfactant includes 1-2 parts by weight of hydroxyethyl cellulose and 3-8 parts by weight of hydroxypropyl methylcellulose, the same below).

B. In parts by weight, 15 parts, 25 parts, 20 parts, 10 parts, 30 parts of ethylene-vinyl acetate copolymer, styrene-stearyl maleate copolymer, polymethacrylic acid Esters, nonionic surfactants, No. 200 solvent oil, tetra-n-butyl titanate as a polymerization catalyst, and a polymerization reaction at a temperature of 200°C for 6 hours to obtain a diesel pour point depressant product B.

C. In parts by weight, 20 parts, 25 parts, 20 parts, 5 parts, 30 parts of ethylene-vinyl acetate copolymer, styrene-stearyl maleate copolymer, polymethacrylic acid Esters, nonionic surfactants, No. 200 solvent oil, tetra-n-butyl titanate as a polymerization catalyst, and a polymerization reaction at a temperature of 200°C for 6 hours to obtain a diesel pour point depressant product C.

D. In parts by weight, 20 parts, 20 parts, 30 parts, 5 parts, 25 parts of ethylene-vinyl acetate copolymer, styrene-stearyl maleate copolymer, polymethacrylic acid Esters, nonionic surfactants, No. 200 solvent oil, tetra-n-butyl titanate as a polymerization catalyst, and a polymerization reaction at a temperature of 200°C for 6 hours to obtain a diesel pour point depressant product D.

E. In parts by weight, 10 parts, 30 parts, 20 parts, 10 parts, 30 parts of ethylene-vinyl acetate copolymer, styrene-stearyl maleate copolymer, polymethacrylic acid Esters, nonionic surfactants, No. 200 solvent oil, tetra-n-butyl titanate as a polymerization catalyst, and a polymerization reaction at a temperature of 200°C for 6 hours to obtain a diesel pour point depressant product D.

F. In parts by weight, 10 parts, 25 parts, 30 parts, 10 parts, 25 parts of ethylene-vinyl acetate copolymer, styrene-stearyl maleate copolymer, polymethacrylic acid Esters, nonionic surfactants, No. 200 solvent oil, tetra-n-butyl titanate as a polymerization catalyst, and a polymerization reaction at a temperature of 200°C for 6 hours to obtain a diesel pour point depressant product F.

Example 2

1. Preparation of ethylene-vinyl acetate

Put vinyl acetate and ethylene into the autoclave according to the molar ratio of 1:2.2, the pressure is controlled at 12Mpa, the temperature is 190°C, and 1wt% initiator azobisisobutyronitrile is used for polymerization reaction for 3 hours to obtain ethylene- Vinyl acetate copolymer.

2. Preparation of styrene-stearyl maleate copolymer

(1) Add styrene and maleic anhydride to the reactor at a molar ratio of 1:2, use dibenzamide peroxide as the initiator, and use toluene as the solvent, heat up to 120°C under constant stirring, and react for 4 hours. That is, a styrene-maleic anhydride copolymer was obtained.

(2) Add stearyl alcohol which is equimolar to maleic anhydride, use p-toluenesulfonic acid as a catalyst, and perform esterification at 150°C to obtain a styrene-stearyl maleate copolymer.

3. Preparation of polymethacrylate

(1) Add methacrylic acid, amyl alcohol, hexanol, heptanol, octanol, lauryl alcohol, and stearyl alcohol to the reaction kettle according to the molar ratio of 1:1.5, and the molar ratio of each alcohol is any ratio , Esterified at 160°C for 3 hours to obtain a monomeric ester.

(2) Add 0.5wt% tetra-n-butyl titanate to the monomer ester as a polymerization catalyst and polymerize at 200°C for 6 hours to obtain polymethacrylate.

4. Prepare pour point depressant G in different parts by weight

In parts by weight, 15 parts, 25 parts, 20 parts, 10 parts, 30 parts of ethylene-vinyl acetate copolymer, styrene-stearyl maleate copolymer, polymethacrylate, Non-ionic surfactant, No. 200 solvent oil, tetra-n-butyl titanate as a polymerization catalyst, polymerization reaction at a temperature of 200°C for 6 hours, and a diesel pour point depressant product G was obtained.

Example 3

1. Preparation of ethylene-vinyl acetate

Put vinyl acetate and ethylene into the autoclave at a molar ratio of 1:2.2, control the pressure at 12Mpa, temperature 190°C, use 1wt% initiator benzoyl peroxide, and polymerize for 3 hours to obtain ethylene-acetic acid vinyl ester copolymer.

2. Preparation of Styrene-Stearyl Maleate Copolymer

(1) Add styrene and maleic anhydride to the reactor at a molar ratio of 1:2.2, use dibenzamide peroxide as the initiator, and use toluene as the solvent, heat up to 120°C under constant stirring, and react for 4 hours. That is, a styrene-maleic anhydride copolymer was obtained.

(2) Add stearyl alcohol which is equimolar to maleic anhydride, use p-toluenesulfonic acid as a catalyst, and perform esterification at 150°C to obtain a styrene-stearyl maleate copolymer.

3. Preparation of polymethacrylate

(1) Add methacrylic acid, pentanol, hexanol, heptanol, octanol, lauryl alcohol, and stearyl alcohol to the reactor in a molar ratio of 1:1.8, and the molar ratio of each alcohol is any ratio , Esterified at 150°C for 3 hours to obtain a monomeric ester.

(2) Add 0.5wt% tetra-n-butyl titanate to the monomer ester as a polymerization catalyst and polymerize at 200°C for 6 hours to obtain polymethacrylate.

4. Prepare pour point depressant H in different parts by weight

In parts by weight, 15 parts, 25 parts, 20 parts, 10 parts, 30 parts of ethylene-vinyl acetate copolymer, styrene-stearyl maleate copolymer, polymethacrylate, Non-ionic surfactant, No. 200 solvent oil, tetra-n-butyl titanate as a polymerization catalyst, polymerization reaction at a temperature of 200°C for 6 hours, and a diesel pour point depressant product H was obtained.

Example 4

1. Preparation of ethylene-vinyl acetate

Put vinyl acetate and ethylene into the autoclave at a molar ratio of 1:2.4, control the pressure at 12Mpa, temperature 190°C, use 1wt% initiator benzoyl peroxide, and polymerize for 3 hours to obtain ethylene-acetic acid vinyl ester copolymer.

2. Preparation of styrene-stearyl maleate copolymer

(1) Add styrene and maleic anhydride to the reactor at a molar ratio of 1:2, use dibenzamide peroxide as the initiator, and use toluene as the solvent, heat up to 120°C under constant stirring, and react for 4 hours. That is, a styrene-maleic anhydride copolymer was obtained.

(2) Add stearyl alcohol which is equimolar to maleic anhydride, use p-toluenesulfonic acid as a catalyst, and perform esterification at 150°C to obtain a styrene-stearyl maleate copolymer.

3. Preparation of Polymethacrylate

(1) Add methacrylic acid, pentanol, hexanol, heptanol, octanol, lauryl alcohol, and stearyl alcohol to the reactor in a molar ratio of 1:1.8, and the molar ratio of each alcohol is any ratio , Esterified at 150°C for 3 hours to obtain a monomeric ester.

(2) Add 0.5wt% tetra-n-butyl titanate to the monomer ester as a polymerization catalyst and polymerize at 200°C for 6 hours to obtain polymethacrylate.

4. Prepare pour point depressant I with different parts by weight

In parts by weight, 15 parts, 25 parts, 20 parts, 10 parts, 30 parts of ethylene-vinyl acetate copolymer, styrene-stearyl maleate copolymer, polymethacrylate, Nonionic surfactant, No. 200 solvent oil, tetra-n-butyl titanate as a polymerization catalyst, polymerization reaction at a temperature of 200°C for 6 hours, and a diesel pour point depressant product I was obtained.

Test Example

Weigh 1g of diesel pour point depressants A, B, C, D, E, F, G, H, and I into 10kg of different standard diesel samples, and measure the freezing point of diesel oil according to the method of GB/T510, and according to SH/T0248 The method is used to measure the cold filter point of diesel oil, and its use effect is detected. The results of the measurement are shown in Table 3 below:

Table 3 is the numerical table of condensation point and cold filter point

Claims (6)

1. A diesel pour point depressant is made up of the following components by weight: 10-20 parts of ethylene-vinyl acetate copolymer, 20-30 parts of styrene-stearyl maleate copolymer, 20-30 parts of polymethacrylate, 5-10 parts of nonionic surfactant, 200 parts No. 25-35 parts of solvent naphtha. 2. The diesel pour point depressant according to claim 1, characterized in that, the preparation method of ethylene-vinyl acetate is as follows: vinyl acetate and ethylene are passed into the autoclave according to the molar ratio of 1:2~2.4 , the pressure is controlled at 10~15Mpa, the temperature is 170~190°C, and ethylene-vinyl acetate copolymer can be obtained by using 1wt% initiator azobisisobutyronitrile or benzoyl peroxide for 3~4 hours of polymerization reaction. things. 3. diesel oil pour point depressant according to claim 1, is characterized in that, described styrene-stearyl maleate copolymer preparation method is: with styrene and maleic anhydride according to molar ratio 1:2 ~2.2 Add to the reaction kettle, use dibenzamide peroxide as the initiator, use toluene as the solvent, heat up to 110-130°C under constant stirring, and react for 4-6 hours to obtain styrene-maleic anhydride copolymer , plus octadecyl alcohol and maleic anhydride in equal molar amounts, using p-toluenesulfonic acid as a catalyst, and esterifying at 150°C to 170°C to obtain a styrene-stearyl maleate copolymer. 4. Diesel pour point depressant according to claim 1, is characterized in that, the preparation method of described polymethacrylate is: methacrylic acid and pentanol, hexanol, heptanol, octanol, lauryl alcohol 1. Stearyl alcohol is added to the reactor according to the ratio of acid-alcohol molar ratio of 1:1.5~2, the molar ratio of each alcohol is any ratio, and esterified for 3 hours at 150~170°C to obtain monomeric ester; then to these Add 0.5wt% tetra-n-butyl titanate to the monomer ester as a polymerization catalyst and polymerize at 200°C for 6 hours to obtain polymethacrylate. 5. diesel oil pour point depressant according to claim 1, is characterized in that, described nonionic surfactant is: the hydroxyethyl cellulose that is 1-2 parts by weight and the 3-8 parts by weight parts of hydroxypropyl methylcellulose. 6. the preparation method of diesel oil pour point depressant as claimed in claim 1 is, may further comprise the steps: (1) Add 5-10 parts of nonionic surfactant to 25-35 parts of No. 200 solvent oil, and disperse at 50°C for 20-30 minutes; (2) Take 10-20 parts of ethylene-vinyl acetate copolymer, add it to the above system, and disperse for 10 minutes at room temperature; (3) Take 20-30 parts of styrene-stearyl maleate copolymer, add it to the above system, and disperse at room temperature for 10 minutes; (4) Take 20-30 parts of polymethacrylate, add it to the above system, and disperse for 10 minutes at room temperature; (5) Diesel pour point depressant is obtained after uniform dispersion.